Thanks Steve
I had been considering the former, but I would expect that there are instances of both. Thanks for the link I will obtain and review.
What I was essentially wondering with my original post was: is the local environment caused when corrosion is occurring beneath a disbonded coating...
I am currently in the process of performing an assessment on an old underground pipe (approx 60 years) which has recently undergone In-Line-Inspection for the first time (High Res MFL).
With no previous inspection data to determine a corrosion rate, I have consulted API RP 581 (section 2.B.12...